A heretofore known printing machine for plastic tile with feeding correction device, referring to FIGS. 5 and 6, has electromagnetic disks 12 fitted to two ends of a first roller 11. The first roller 11 is located on a platform 13. A printed layer 14 is wound around the first roller 11, and has a central sensing line 141 and a first length sensing line 142 on tow edges. A printing roller 15 is provided at other end of the machine with a sensing device 16 arranged between it and the first roller 11. The sensing device 16 has a central electric sensing eye 161, and an electric length sensing eye 162. The printing roller 15 has a second length sensing line 151, and several inspecting points 152 in association with the length sensing line 142. The inspecting points 152 are electrically connected to an electric inspecting eye 153. The printed layer 14 is coupled to a bottom layer 17. Before the printed layer 14 is fed to the printing roller 15, both the sensing device 16 and the electric eyes 153 will get data in respect of the position and size of the print pattern. The data is then sent to memory units 181 and 182, and caculated by a computer calculation unit 183. Thus, the calculation unit 183 can control the electromagnetic disks 12 for adjusting speed of the first roller 11. Moreover, a second calculation unit 184 can also control a motor 19 for adjust the position of the platform 13 and the first roller 11. Thus, in printing on the plastic tile, the feeding speed and the position thereof in relation to the related components of the printing machine can be adjusted in the process of printing to eliminate errors.
However, it is found that the printing machine still has undesirable features as follows.
1. The electric eyes 162 and 153 are utilized to effectively sense the position and the electromagnetic disks 12 are utilized to control the feeding speed of the printed layer 14 for accurately matching the printed layer 14 and the printing roller 15. For increasing the accuracy, the plastic tile not only has to be made to have a specific size but print many length sensing lines 142 on it. There are usually 45-65 lines on it. Consequently, the material cost is relatively high. PA1 2. Correspondingly, the printing roller 15 has to have same numbers of length sensing lines 151, and inspecting points 152. This will raise the cost. Furthermore, the electric inspecting eye 153 is difficult to install, and has high error rate. PA1 3. The Omission and distorsion of data happen frequently because the electric eyes 153 and 162 have many points to sense. Consequently, the failure rate of products is relatively high. PA1 4. Because the first roller 11 is pulled to move by the printing roller 15, the first roller 11 cannot be controlled in respect of feeding of the printed layer. And the fact that the plastic tile is heated in the process of printing and so lengthened is not taken into consideration. The print pattern usually has to go over tens of plastic tiles before it is finally adjusted to a proper position 2 on the plastic tile. Consequently, a worker is needed to watch in the whole process of printing in order to reduce the failure rate. PA1 a platform, PA1 a first roller arranged on the platform; the first roller having a first layer wound therearound, PA1 an electric anti-diversion eye capable of detecting an anti-diversion line on the first layer, PA1 an electric length-sensing line capable of detecting length sensing line on the first layer, PA1 a computer calculation unit, data acquired by the anti-diversion eye being sent to the computer calculation unit for calculation, the caculation unit activating a motor for adjusting the relative position between two ends of the first roller according to the data, PA1 a printing roller having a print pattern thereon, the printing roller being provided with a code translator on the spindle thereof, PA1 a feeding roller driven by a feeding motor, the calculation unit calculating data from the electric length-sensing eye and the first code translator to adjust the feeding motor in respect of the speed in order for the first layer to match the print pattern of the printing roller, PA1 a monitor provided for showing errors of the position of the feeding roller relative to the printing roller, PA1 a synchronous error correcting device provided for adjusting the position of the electric length-sensing eye when same has to be moved to be adapted for various sizes of plastic tiles, PA1 a second code translator fitted to the feeding roller, the second code translator providing the calculation unit with data concerning the speed of the feeding motor, the feeding motor being capable of being quickly adjusted such that same and the printing roller can run in a synchronized manner.